Added version 1.2 to docs versions

[shimwell]

Description

This pr adds version 1.2 to docs drop down list for versions . We should merge this after releasing version 1.2

Checklist

• I'm making a PR from a feature branch on my fork into GEOUNED-org/GEOUNED/dev branch
• I have followed PEP8 style guide for Python or run a formatter such as black or ruff format on my code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works